Motor-controlling means



Jan. 26 1926.

B. E. MHLLS MOTOR CONTROLLING MEANS Filed Feb. 9, 1925 2 Shoots-Sheet llllllllllh` Jan. 26, 1926.

B. E. MILLS MOTOR CONTROLLING MEANS 2 Sheets-Sheet 2 Filed F'eb. 9, 1925FE f I I J/ l Patented Jan. Z6, 1926.

UNITED STATES PATENT OFFICE,

BERTIE E. MILLS, OF OAK PARK, ILLINOIS, ASSIGNOR 'EO MILLS NOVELTYCOMFANY, F CHICAGO, ILLINOIS, .A CORPORATION OF ILLINOIS.

MOTOR-CONTROLLIIIG MEANS.

Application filed February 9, 1925. Serial No. 7,908.

T0 all whom fit may concern.'

Be it known that I, Bumm E. MILLS, a citizen of the United States,residing at Oak Fark, in the county of Cook and Sta-te of Illinois, haveinvented a new and useful Motor-Controlling Means, of which thefollowing is a. specification.

This invention relates particularly to motor controlling means adaptedfor use in controlling the speed of a bow-actuating motor for a stringedinstrument musical machine.

Mtachines of the character referred to are disclosed, for example, invarious United States Patents granted to Mills Novelty Company, many ofsuch patents having been granted upon the applications of Henry l.Sandell.

In the Mills type of machine, during the playing of the stringedinstrument, the rotating bows are driven continuously by an elec-tricmotor, and the notes are sounded by depressing` the bows and actuatingthe lingering devices associated with the strings of the instrument. Thedepression of the bows in Contact with the strings and the actuation ofthe fingering devices are controlled by electric circuits. rlhesecircuits may be controlled by a music sheet which passes between a metalroll, or tracker-bar, and associated contacts, in a well known manner;or said circuits may be controlled by mea-ns of keys mounted on aconsole and operated like the keys of a piano. Ordinarily, however, inthe commercial machines, the tracker board control of the playing of thenotes is employed.

The music sheet may also be provided with a series of slots adapted tocontrol the expression of the instrument. In such case, the music sheethas associated therewith a series of contacts which control theexpression-circuits. However, if desired, the exa pression-circuits maybe controlled from a console by means of suitable pedals.

The primary object of the present invention is to associate with theexpression circuits governor-controlled circuits which may modifying theaction of the expression-circuits.

A further object is to provide an improved centrifugal governor whichcan be usefully employed in controlling the speed of an electric motor.

It isusual, in the Mills type of machine,l

to vary the expression of the stringed instrument by varying the speedof the motor which actuates the bows. In the normal playing of theinstrument, the motor operates continuously, the circuit being closed inany suitable manner. In the coin-controlled machines, the main circuitis closed by introducing a coin into the machine. The changes in speedof the motor occur when the expression-circuits act to vary the speed,as by cutting in, or cutting out, resistance coils with which the fieldof the motor is equipped.

The invention is illustrated in its preferred embodiment in theaccompanying drawings, in which- Fig. l shows an elevational view of abowmotor and the attendant parts, the mechanism being shown mounted upona bracket (shown brokenly); 2, a sectional view taken as indicated atline 2 2 of Fig. l and showing the centrifugal governor employed, Fig.3, a broken sectional view taken as indicated at line 3 3 of Fig. 2; andF ig. 4f, a diagrammatic view illustrating the motor circuits, theexpression circuits, and the governor-control circuits which serve tomodify the action of the expression circuits.

lin the illustration given, provision is made for varying speeds of thebow-motor to obtain effects, as follows: extra soft, soft, normal, loud,double loud, triple loud.

As indicated above, the normal speed is independent of theexpression-circuits. On the other hand, the expression-circuits controlthe expression effects listed, and the governor-controlled circuitsmodify the effect of the expression-circuits.

In the drawings, M designates a bowmotor; M', a centrifugal governorassociated therewith; and M2, the bow-actuated shafts operated by themotor. The armature of the motor is designated M3, and the commutatorbrushes are designated M4.

The motor is provided with exciting coils, or field coils, whichpreferably are in the nature of four spools, two of which are located oneach side of the armature. Each of three of the spools is provided withtwo distinct field coils, and the fourth spool is provided with a singlefield coil. These coils are used in various combinations to vary theexcitation of the liclds.

In Fig. 4l, the inner windings of the three spools mentioned aredesignated A, B and C, respectively, and the winding of the fourth spoolis designated D. The outer windings of the three spools are designatedF, G and E, respectively.

The motor is operated through av main circuit comprising a positive line1 and a negative line 2, which are connected, respectively, with apositive binding post N and a negative binding post N The circuit may beclosed, in any suitable manner, to cause the motor N to run at normalspeed. For example, the circuit may be closed by coin-controlled means.1n the normal operation, the current passes to the binding post N,thence through a conductor 3 to the inner coil A, thence through aconductor t to a binding post L, thence through a conductor 5 to theinner coil B, thence through a conductor 6 to a binding post L L, thencethrough a conductor 7 to the coil C, thence through a conductor 8 to a.binding post L L L, thence through a conductor 9 to the armature, thencethrough a conductor 10 to a binding post 11, thence through a conductor12 to the coil D, thence through a conductor 13 to the negative bindingpost N. After the current passes through the coil C, a portion passesthrough a conductor 8a to the coil E, and thence through a conductor 8btothe conductor 10. Thus, a shunt circuit is maintained through the coilE and across the armature.

Vhile the various coils may be given any desired resistance, it may bestated, as an example, that the coils A, B, C and G may have aresistance of 125 ohms each; the coil F may have a resistance of 300ohms; the coil D may have a resistance of 1GO ohms; and the coil E mayhave a resistance ot tOO, 500, or 600 ohms. In the illustration given,the line 8b is taken from the intermediate lead of the coil E, and sothe coil may be said to have a resistance of 500 ohms. The lower theohmic resistance of the coil E, the slower the speed oi' the armature.lt the resistance of the coil E be increased, the effect is to causemore of the current to go through the armature and so increase thespeed.

In the illustration given in Fig. l, the expression-circuits arecontrolled by a metal roll, or tracker-bar, 14, which is connected withthe line 1 by a conductor 142, a music sheet 15, and a series of contactbrushes S, S S, L, L L, and L L L. The eX- pression-circuits areconnected with the contacts, or brushes, just mentioned. Thus, thecontact S is connected by a conductor S2 with the binding post S; theContact S S is connected by a conductor S2 S2 with the binding post S S;the contact L is connected by a conductor L2 with the binding post L;the Contact L L is connected by a conductor L2 L2 with the binding' postL L; and the contact L L L is connected by a conductor L2 L2 L2 to thebinding post L L L.

lVhen, in the playing of the instrument, the contact L encounters a slotin the music sheet andv comes into contact with the positive energizedroll 111:, the current passes through the conductor L2 directly to thebinding post L, and thus cuts eut the coil A, causing the motor speed toincrease above the normal; similarly, when a circuit is establishedthrough the conductor L2 L2, the current passes directly to the bindingpost L L, and so cuts out the coils A and B trom the field, thus causinga greater increase in the speed oi the motor; and similarly, when thecircuit is established through the conductor L2 L2 L2, the currentpasses directly to the binding post L L L, and so cuts out theresistance coils A, B and C from the iield, thus causing the motor tooperate at highest speed. On the other hand, when the circuit isestablished through the conductor S2, the current passes directly to thebinding post S, and thence through a conductor 16 to the coil G, thencethrough a conductor 17 to the binding posts S S, thence through aconductor 18 to the coil F, thence through a conductor 19 to the coil D,thence through the conductor 13 to the negative binding post N, andthence to the return line Q. Thus, the coils F and G are cut into thefield circuit, it being noted that the coil D always remains in theiield circuit. Again, when the circuit is established through theconductor S2 S2, current passes to the binding post S S, thence throughthe conductor 18 to the coil F, thence through the conductor 19 to thecoil D, and thence to the return line 2. Thus, the 300 ohm coil F is cutinto the circuit in series with the 1GO ohm coil D. rl`his allows morecurrent to pass through the lield windings than when the conductor S2 isin circuit; hence, the slowest speed ot the motor is obtained when theconductor S2 S2 is in circuit. This corresponds with the softest tone ofthe instrument, due to the slowest rotation oit' the bow.

lt may happen that the bow-motor will run too fast, or too slow, due toa variation in load, for example. rEhe centrifugal governor ill operatesas a crush in such case. in the illustration given, a conductor N leadsto a vibratory contact member 20, so that the member 20 is positively'energized. This member vibrates between a pair oit contacts 21 and 22.The contact 2l is connected by a conductor L2Li with the binding post LL; and the contact 22 is connected by a conductor S3 with the bindingpost S.

The vibrator contact member 2() is controlled by a centrifugal governor'M. It is carried by a bell-crank lever 22B which is insulatinglysupported cn a pivot 24 carried by a depending arm 95 ot a bracketmember lil 26 which is mounted on the motor frame. A spring 27 connectedby means of an insulating libre link 28 with the bell-crank lever 23tends to move the arm 23 towards the motor. rlhis is opposed by aplunger which is mounted to move freely in a longitudinal direction inone end or" a hub, or sleeve, 30, whose opposite end is secured, as by aset screw 31 to the motor shaft 32. T he inner end of the plunger 29bears against a lever 33 which is connected with a pivot 34eeccentrically carried by the sleeve 3 rlhe sleeve is slotted and thelever extends through and works in the slot. llfhe sleeve is equippedwith laterally extending hubs, or arms, 35, which register with bearings35 with which a wheel-rim 36 is provided at diametrically oppositepoints. Screws 3T are threaded through the supports 3, and are providedwith reduced inner ends 3? on which the arms 35 are journalled. A spring38 connects the rim, or the lever, near its point oi attachment with therim with the inner end of the sleeve 30. This spring tends to move thewheel, or rim, to an oblique position and bring a stop-shoulder 83a otthe lever against the circumferential sur- .tace of the inner portion ofthe sleeve 30. lVhen the motor shaft is in rotation, centrifuga-l Jforcetends to move the rim, or wheel, 36a to a plane perpendicular withrespect to the shaft. When this occurs, the wheel-rim, swinging aboutthe pivots 3T, moves the lever 38 and causes it to push the arm 2,a ofthe bell-crank lever 23 to the right, as viewed in Fig. 1. The motor mayattain sutlicient speed to bring the wheel 36 to a perpendicularposition, in which position the vibratory contact member 2O comes intoengagement with the contact member 22. vWhen this occurs, current maypass through the branch S3 to the binding` post S, thus operating to cutin the coils G and F and place them in series with the iield coil l),thus tending` to slow down the motor. The member 2O may make vibratorycontact with the member 22 in such manner as to keep the motorsubstantially at constant speed.

On the other hand, should the motor operate too slowly, the member 2Owill make contact with the member 2l, and thus energize the branch L3 L3which leads to the binding post L L. When coils A and B will be cut outof the circuit, and the speed of the motor will be increased. The member2O may vibrate close to the member 2l, and keep the motor substantiallyat constant speed.

it will be noted that in the arrangement shown, the effect ofestablishing a circuit through the branch L3 L3 to the binding post L L,momentarily, is the same as feeding current from the roller la throughthe conductor L2 L2. ln other words, there this occurs, the

may be a momentary boost in the speed ot tl e motor as, tor example,where the speed may be too slow when cit-.ier the conductor S2 or theconductor S2 S2 is in circuit. Also, the elica-t or momentarilyestabliol ing a circ-uit through a branch to the binding post S is thesame as feeding current -ror the roller le through the conductor Si tothe binding post S, which cuts in resistance as previously described.Vlhis action may occur under the intiuence ot the governor when one otthe loud expressions is operating.

ln Fig. l, th spools which form portions ot the lield windings and whichappear in the view are the spools which contain the .inner winding l5and the outer winding G and which contain the inner winding C and theouter winding This is indicated on the pools, in the illustration. rlheconnec- 'ons between the coils and the binding posts are omitted jtroi.Fig. l, 'for clearness oi illustration.

The bow-actuating shafts M2 #e driven by the motor shaft 32 in any.uitablc inanner. Usually this is by means ot wormg'ear connections.

From the. description given, it will be understood that in theembodiment illustrated the expression-circuits automatically control thespeed of the motor, but inasmuch as this control may not be sutiicientlyaccurate, the control exercised by the expression-circuits is modiliedby the control exercised by the governor. rllhe circuits controlled bythe governor may operate to oppose the action o'l' theexpression-circuit.'

For example, when the loud expression is being used and the circuit isestablished through the conductor L2, the motor may run too tast, inwhich case the Vibratory member 2O will engage the contact member 22 andclose the circuit through the branch S3, thereby cutting in resistanceand slowing down the motor, as described.

Ordinarily, in the normal operation of the motor, the vibrator-y contactmember 2O remains in the intermediate position shown in Figs. l and 4.lt', for any reason, the speed of the motor should drop sufliciently,the member 2O will engage the member 2l and thus cut out the coils A andB, causing the motor to speed up. On the other hand, should the speed ofthe motor increase unduly for any reason, the member 2O will engage themember 22 and cut in the resistance coils G and F, thus causing themotor to slow down.

The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, but the appended claims should be construed as broadly aspermissible, in view of the prior art.

l,Vhat l. regard as new, and desire to secure by Letters Patent, is:

l. In motor mechanism for violin players and the like, the combinationof a motor provided Wit-li field coils normally in the main circuit ofthe motor, expression-circuits adapted to be closed to cut out one ormore of said coils, a governor-controlled circuit adapted to cut out oneor more of said coils and thus modify the action of saidexpression-circuits, and a. centrifugal governor actuated by the motorand controlling said last-named circ-uit.

2. In motor mechanism for violin players and the like, the combinationof a motor provided with a series of field coils which are normally inthe main circuit of the motor and provided also with coils which arenormally out of circuit, expression-circuits adapted to cut out one ormore of said firstnamed coils and to cut in one or more of saidsecond-mentioned coils, and governorcontrolled mechanism equipped withcircuits adapted to modify the action of said eX- pression-circuits.

3. In motor i'nechanism for violin players and the like, the combinationof a motor provided with aplurality of field coils which are normally inthe main circuit of the motor and provided also with a plurality ofcoils which are normally out of said circuit, a plurality ofexpression-circuits adapted to be closed to cut out said first-namedcoils or some of them and to cut in. said secondnamed coils or some ofthem, a governor device actuated by the moto-r, and circuits controlledby said governor device and adapted to cut out one or more of saidfirstnamed coils or to cut in one or more of said second-named coils,for the purpose set forth.

Il. In motor mechanism for violin players and the like, the combinationof a` motor provided with a field coil normally in the main circuit ofthe motor and provided with a field coil normally out of said circuit,expression-circuits adapted to be closed to cut out said first-namedcoil or to cut in said second-named coil, a governor device actuated bythe motor, and circuits so controlled by said governo-r device as to beoperative to cut in said second-named coil While said first-named coilis cut out through the medium of the expression-circuit which con troisit, and vice versa.

In motor mechanism for violin players and the like, the combination of amotor provided with a plurality of field coils which are in circuit inthe normal operation of the motor and provided With a. plurality offield coils which are out of circuit in the normal operation of themotor, a plurality of expression-circuits controlling the cutting` outof said first-named coils and the cutting in of said second-named coils,said expression-circuits being equipped With contacts and a eo-actingenergized tracker-bar, a governor actuated by the motor, and governorcontrolled circuits, one of which is adapted to cut in one or more ofsaid second-named coils at a. time when one ore more of said first-namedcoils are out out, and the other of Which is adapted to cut out one ormore of said first-nan'ied coils at a time when one or more of saidsecond-named coils are cut in.

BERTIE I). MILLS.

